Bugs item #1075703, was opened at 2004-11-29 20:54 Message generated for change (Comment added) made by tim_one You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1075703&group_id=5470
Category: Threads >Group: 3rd Party Status: Closed Resolution: Invalid Priority: 5 Submitted By: Andi Vajda (andivajda) Assigned to: Nobody/Anonymous (nobody) Summary: PyGILState_Ensure() deadlocks (ver 2.4) Initial Comment: PyLucene (http://pylucene.osafoundation.org) wraps libgcj with python. Python objects are also wrapped by java objects. The ref count of the python is incremented in the wrapping java object constructor and is decremented in the wrapping java object's finalize() method. Yes, finalize() is not a reliable means of cleaning memory up but, so far, I wasn't able to figure out a better way to do this. The finalize() method runs in its own libgcj finalizer thread. It has to acquire the GIL before it can call Py_DECREF() is my understanding. The java finalize() calls this code in PyLucene: void finalizeObject(PyObject *object) { #if PY_VERSION_HEX >= 0x02040000 PyGILState_STATE state = PyGILState_Ensure(); Py_DECREF(object); PyGILState_Release(state); #endif } When compiled with python 2.4c1, this mostly works. Except that it deadlocks, every now and then. If I comment this code out, no deadlock. I also verified that the finalizer is called at most once per such object. I realize that reproducing this bug maybe hard, building PyLucene is not particularly easy, unless you have gcj ready. If you contact me, I'm more than willing to help in providing all that's needed to reproduce this. I've seen the deadlock on Mac OS X 10.3.6, my main development OS. For what it's worth, I also tried this with python 2.3.4 (including threadmodule.c patch made in September, related to GIL function usage). ---------------------------------------------------------------------- >Comment By: Tim Peters (tim_one) Date: 2004-12-18 23:19 Message: Logged In: YES user_id=31435 Changed Group to 3rdParty. ---------------------------------------------------------------------- Comment By: Michael Hudson (mwh) Date: 2004-12-05 05:35 Message: Logged In: YES user_id=6656 Speaking as a Python developer, phew :) ---------------------------------------------------------------------- Comment By: Andi Vajda (andivajda) Date: 2004-12-04 23:15 Message: Logged In: YES user_id=1139346 I finally tracked down this bug to gcj bug <a href="http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16478";>16478</a> which is fixed in gcj version >= 3.4.2. I am hence closing this python bug as invalid. ---------------------------------------------------------------------- Comment By: Andi Vajda (andivajda) Date: 2004-12-03 22:42 Message: Logged In: YES user_id=1139346 I've been running the same test loop on Gentoo/2.6/python 2.4 and was not able to get it to deadlock so far. This bug could be limited to Mac OS X. ---------------------------------------------------------------------- Comment By: Andi Vajda (andivajda) Date: 2004-12-03 22:10 Message: Logged In: YES user_id=1139346 I verified this now with python 2.4 final. It still happens as tested on Mac OS X. I was also able to narrow it down to a unit test, that when run repeatedly will eventually lock up. It is attached. If you need assistance building PyLucene from sources, or want me to provide a binary, let me know. At the moment, to reproduce this bug, it is best to build PyLucene from subversion. See http://pylucene.osafoundation.org for more information. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1075703&group_id=5470 _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
